1. Field of the Invention
The present invention relates to medical needle devices, and more particularly relates to medical needle devices having a shield for the reduction of needlestick injuries, in which a used needle can be stored safely.
2. Related Background Art
Conventionally, contamination and infections due to needlestick injuries with injection needles or puncture needles have been a problem in medical facilities. In particular, recently, as hepatitis B, hepatitis C, HIV (human immunodeficiency virus) and the like have received widespread attention, there is a strong demand for means that actively reduce such needlestick injuries.
As a means for preventing such needlestick injuries, a configuration in which a cylindrical shield is provided so that the shield can slide with respect to the injection needle is known. That is, depending on the sliding position of the shield, the injection needle is either exposed or it is contained in the shield. When disposing of a used injection needle or a used puncture needle, a needle is slid into the shield so as to be contained therein.
Injection needle devices described in JP H6(1994)-7861B, JP H5(1993)-300942A and U.S. Pat. No. 4,170,993 are known as examples of such configurations. These injection needle devices are a winged injection needle device that is used widely in a procedure such as a liquid infusion, a blood transfusion, extracorporeal blood circulation, or the like. In the winged injection needle device, the wings are attached to the outer peripheral surface of a slidable cylindrical shield, and the wings slide together with the shield on the outer side of the injection needle. In order to prevent needlestick injuries after use of the injection needle, the tip of the injection needle can be covered with the shield by sliding it.
In the course of using such an injection needle device having the cylindrical shield, a mechanism is necessary for limiting the position of the injection needle relative to the shield so as to maintain a predetermined state with the needle protruding from the shield. Especially, during the puncturing action, the injection needle should be held so as not to be pushed into the shield. In addition, after the puncturing action, in order to retain the puncturing state of the injection needle, the injection needle might be required to be held at a predetermined position relative to the shield. This is because, even when the shield is fixed to the punctured portion of the patient for preventing the injection needle from leaving the retained state, if the injection needle is easily moved within the shield, there is the risk that the injection needle comes off the punctured portion of the patient. Each injection needle device described in JP H6(1994)-7861B, JP H5-300942 A or U.S. Pat. No. 4,170,993 has a configuration for holding a predetermined state of an injection needle relative to a shield.
Furthermore, at the time of storing the injection needle in the shield, it is desirable that the injection needle can slide easily with respect to the shield. In the case of the configuration described in JP H6-7861B, however, in order to store the injection needle in the shield, the injection needle has to be retracted in the shield against a holding force for holding the injection needle with respect to the shield while the holding force is still applied thereto. In the case of the configuration described in JP H5-300942 A, at the time of storing the injection needle in the shield, the force for holding the injection needle can be weakened. Due to its configuration, however, it is difficult to weaken sufficiently the force applied when the injection needle is stored in the shield while ensuring the sufficiently large force for holding the injection needle with respect to the shield. According to the configuration described in U.S. Pat. No. 4,170,993, such conditions can be satisfied.
In the injection needle device described in U.S. Pat. No. 4,170,993, however, a configuration for holding the injection needle forms an obstacle, which makes it difficult for the injection needle to rotate with respect to the shield in the usage state in which the injection needle protrudes from the shield.
In order to adapt to various operations suitably, it is desirable that, in the usage state in which the injection needle protrudes from the shield, the injection needle can rotate with respect to the shield. For instance, in order to make an angle of a blade surface of the needle after puncturing different from that during the puncturing, the injection needle has to be rotated. Also, in both of the configurations described in JP H6(1994)-7861B and JP H5(1993)-300942A, it is difficult to make the injection needle rotatable with respect to the shield in the usage state in which the injection needle protrudes from the shield.
Although the above problems are described referring to the example of the winged injection needle device, these problems arise commonly also in injection needle devices without wings.